I've always found that a bike cover is very cheap insurance. I've commuted to work for years and always covered the bike while at work and that tends to keep people away. If someone really wants it there's not much you can do but a simple out of sight out of mind solution works well.

Agreed, I do the same and not with some fancy pants BMW cover, but the cheapest looking, dirtiest cover i could find. So far (knock on wood) to pretty good effect.

I also lock the steering, chain the rear wheel and set the factory alarm. To my mind the alarm is less for anti-theft effect and more for moron control (I've come out of my apartment to see people sitting on previous bikes I've owned **GRRRRR!**) and to keep the Braille parkers at bay. There's nothing worse than some jagoff trying to parallel park his Datsun knocking over your bike. Last week in fact, I heard the alarm going off, ran to the window and had to (ahem) educate the moron stepping out of his Ford Escort to figure out what that noise was that "Gee, I didn't mean to touch it" is not an acceptable response.